1. Field of the Invention
The present invention relates to a release bearing used in a friction clutch of an automobile or the like, and more particularly to a release bearing suited to a so-called pull type clutch, that is, a clutch in a structure to cut off the clutch as the diaphragm spring is pulled by the release bearing.
2. Description of the Prior Art
Generally, a release bearing is composed of a case and a bearing main body. The case is an assembly of a sleeve (a tubular member) and a case, and it is slidably supported in a state of direct contact of the sleeve to the quill fixed on the transmission housing, and the case is driven in the axial direction by the lever mechanism interlocking with the clutch pedal. The bearing main body is held on the case, and is coupled with the diaphragm spring of the clutch.
In the pull type clutch, in order to pull the diaphragm spring by the bearing main body in the clutch cut-off action as stated above, the bearing main body is fixed to the diaphragm spring. Accordingly, in a general clutch, for servicing of the clutch, when dismounting the transmission housing from the clutch housing, the quill fixed to the transmission housing is drawn out of the release bearing. At the time of drawing out, the input shaft end portion of the transmission positioned inside the quill also passes through the inside of the release bearing.
Incidentally, in this drawing process, the input shaft may be deviated or inclined in the radial direction with respect to the center line of the release bearing. In the portion projecting from the quill of the input shaft, there is a spline for coupling the clutch disc. As a result, in the drawing process, the spline of the input shaft may collide against the inner surface of the sleeve, that is, the sliding surface finished at high precision, to injure it. If the sleeve is thus injured, it is substantially impossible to replace only the sleeve because of the structure of the release bearing, and it is necessary to replace the entire release bearing. As a result, considerable labor and cost are needed.
Still more, in the conventional structure, since the quill and sleeve are both made of metal, the quill may be worn and must be replaced, which also means labor and cost.
In addition, in the conventional structure, it is necessary to apply grease on the contact surfaces of the quill and sleeve in order to reduce the sliding resistance of the two, and it takes time in assembling work.
The invention is therefore intended to present a structure capable of solving the above problems.